Multiple tubing string well completion equipment



Se t. 4, I962 J. D. WATTS ETAL 3,052,301

MULTIPLE TUBING STRING WELL COMPLETION EQUIPMENT Filed May 15, 1957 4 Sheets-Sheet 1 \Qi v Ill/ll D. WAT

C. IREL D l 1962 J. D. WATTS ETAL 3,952,301

MULTIPLE TUBING STRING WELL COMPLETION EQUIPMENT Filed May 15, 1957 4 Sheets-Sheet 2 FIG.2

JOHN D. WATTS JAMES C. IRELAND ATTORNEY 1N VENTORS Sem. 4, T J. D. WATTS ETAL. 3,052,301

MULTIPLE TUBING STRING WELL COMPLETION EQUIPMENT Filed May 15, 1957 4 Sheets-Sheet 3 7 fi I'ro I94 494 /-rr2 192 we I88 22 i 230 T3 '73 I44 {I 48 I46 I78 ggg 9s -|oe as 5 y 7 1 -56 2o INVENTORS JOHN D. WATTS 2 JAMES c. IRELAND ATTORNEY Sept. 4, 1962 J. D. WATTS ETAL MULTIPLE TUBING STRING WELL COMPLETION EQUIPMENT Filed May 15, 1957 4 Sheets-Sheet INVENTOR WATTS JAMES C. QRELAND M QM W JOHN D.

ATTORNEY United States Patent 3,952,301 MULTIPLE TUBENG STRING WELL CQMPLETION EQUIPMENT John D. Watts and .iames C. Ireland, Houston, Tex., as-

signors to Gray Tool Company, Houston, Tex., a corporation of Texas Filed May 15, 1957, Ser. No. 659,424 Ciaims. (Ci. 166-97) This invention relates to oil well completion equipment and more particularly to equipment of this type arranged to operate in wells having multiple tubing strings.

The use of multiple tubing strings is well known and has the advantage that flow can be obtained at difierent levels in the well through separate tubing strings. It is understood that the term multiple as herein used in cludes the provision of two, three or more tubing strings circumferentially arranged or annularly spaced with respect to each other. In the multiple completion equipment heretofore utilized, and more particularly the Christmas tree equipment, a one-piece master control manifold valve embodying multiple valve operators or multiple master control valves were necessary. Such master control valves were conventionally utilized below the flow head or lateral pipes leading from the tubing strings to the control valves therefor.

An object of the present invention is to provide multiple well completion equipment which requires the provision of but a single master control valve that can be alternatively utilized to gain controlled access to any one of the multiple tubing strings within the well.

In its broad aspects the invention contemplates the use of rotatable cap means having an offset access opening which may be aligned with any one of the multiple tubing strings so that an operator may gain controlled access thereto. The invention further contemplates the provision of removable plugs which serves to close ofi? access to the tubing strings under normal conditions and improved means for removing and inserting such plugs under controlled conditions so that access can be had to any one of the tubing strings for any desired purpose.

Accordingly, it is another object of the present invention to provide oil well completion equipment embodying an improved rotatable cap having an access opening formed therein for the purposes noted above.

Still another object of the present invention is the provision of oil well completion equipment of the type described embodying improved means for plugging the access to the tubing strings in normal operation and improved means for removing the plugs under controlled conditions so that access will be obtained.

Still another object of the present invention is the provision of a rotatable cap of the type described having improved means embodied therein for removing and inserting access plugs so as to permit controlled access to the tubing strings.

These and other objects of the present invention will become more apparent during the course of the following detailed description and appended claims.

The invention may best be understood with reference to the accompanying drawings wherein an illustrative embodiment is shown.

In the drawings:

FIGURE 1 is a top plan view of oil well completion equipment embodied in the present invention, with the master control valve removed;

FIGURE 2 is a cross-sectional view taken along the line 22 of FIGURE 1 and showing the equipment with the master control valve connected thereto;

FIGURE 3 is a cross-sectional view taken along the line 3-3 of FIGURE 2;

FIGURE 4 is a vertical-sectional view of a modified form of oil well completion equipment embodying the features of the present invention, showing the same with an access plug removed;

FIGURE 5 is an enlarged fragmentary vertical-sectional view of the structure shown in FIGURE 4 with the plug in operative position; and

FIGURE 6 is a fragmentary top plan View of the structure shown in FIGURE 4.

Referring now more particularly to FIGURES 1-3, there is shown oil well completion equipment which in cludes the usual casing or tubing head 14) having a central vertical bore 12 extending therethrough, the upper portion of which is tapered upwardly and outwardly to form a frusto-conical hanger seat 14. Extending radially outwardly above the seat 14 is an annular flange 16 which serves to connect the tubing head to the remaining equipment. The tubing head 10 may also include the usual lateral outlets 18, which are connected through suitable valves (not shown) to other equipment utilized in the formation of the well apparatus.

Landed within the seat 14 is a multiple tubing string hanger 20 having a lower portion provided with an inwardly and downwardly extending exterior frusto-conical seating surface 22 arranged to engage the seat 14 of the tubing head. As is usual, the seating surface 22 is preferably grooved to receive annular sealing elements 24, which serve to provide a pressure-tight seal. between the hanger and the tubing head. The exterior surface of the upper end of the hanger 20 extends upwardly and inwardly to form an annular shoulder 26, which receives the inner end of a locking screw 28 threadedly mounted within the flange 16 of the tubing head. The locking screw 28 serves to retain the hanger 20 in its landed position on the seat 14.

Extending vertically through the hanger 2.0 is a plurality of bores 30 for receiving tubing strings, generally indicated at 32. It will be understood that two, three or more of such bores may be provided and in the hanger illustrated in the drawings, three bores are provided for receiving three tubing strings.

As best shown in FIGURE 2, in constructing the Well, the hanger 20 is mounted on the first tubing string and run into the well through conventional control equipment, such as a master drilling valve and a pair of blowout preventers (not shown), until the same is landed on the seat 14. When the first tubing string has reached its proper depth, a tubing hanger bushing 34 is made up in the string and landed in its associated bore 30. As best shown in FIGURE 2, the hanger bushing 34 comprises a tubular body having a lower portion 36 suitably secured to the upper end of the tubing string 32 by any suitable means, such as threads or the like. The hanger bushing 34 also includes an enlarged upper portion 38, which forms a lower inwardly and downwardly tapering exterior seating surface 40 arranged to land and engage upon an upwardly and outwardly tapering annular seating surface 42 formed on the upper end of each bore 30. As before, the hanger seating surface 40 is preferably grooved to receive annular sealing members 44 to provide an effective pressure-tight seal between the hanger 20 and the hanger bushing 34. The enlarged upper portion 38 of the hanger bushing also provides an upper seating surface 46 which extends upwardly and inwardly for purposes hereinafter to be more fully described. The surface 46 is also grooved to receive suitable annular sealing elements 48.

The interior surface of the hanger bushing 34 is threaded, as indicated at St for receiving the lower end of a pipe or tubing (not shown) used to lower the tubing string 32 carried by the hanger bushing 34 into the well.

Formed just below the threads 56 in the interior of the hanger bushing 34 is an inwardly and downwardly extending shoulder 52 and disposed in vertically spaced relation from the shoulder 52 below the same is an annular groove 54. The shoulder 52 and annular groove 54 are adapted to cooperate with certain parts of a back-pressure valve assembly, generally indicated at 56, in a manner hereinafter to be more fully described. The back-pressure valve assembly 56 is inserted within the hanger bushing 34 when the latter is made up in the tubing string and serves as a flow preventer when the hanger bushing is landed on the seat 42.

It will be understood that any type of back-pressure valve assembly may be utilized in landing the individual tubing strings on the hanger seats 42 and the particular back-pressure valve assembly 56 is illustrated merely to more particularly emphasize the operation of the present invention. As best shown in FIGURE 2, the back-pressure valve assembly 56 comprises a main body or an upper sleeve member 58 having exterior threads 60 formed on the upper portion thereof and its lower end exteriorly threaded to engage within the interiorly threaded upper end of a seal retaining intermediate member 62. Formed on the exterior surface of the main body 58 intermediate the ends thereof is an exterior annular shoulder 64 providing an upwardly and inwardly extending frusto-conical wedge surface '66. An annular sealing element 68 is mounted in surrounding relation to the lower end of the main body 58 in engagement with the shoulder 64 and is retained in position by engagement with the seal retaining intermediate member 62. The lower end of the latter is exteriorly threaded to receive the interiorly threaded upper end of a lower cage member 70. The engagement of the upper end of the cage member with the lower end of the intermediate seal retaining member 62 also serves to secure an annular seat element 72 in a position immediately below the lower end of the intermediate member 62.

The cage member 70 is a skeletonized structure and has mounted therein a ball valve 74 arranged to engage the seat member 72. The ball is resiliently biased toward the seat by means of a coil spring 76 having its upper end in engagement with the ball and its lower end in engagement with the lower end of the cage member 70. A wedge carrying sleeve 78 is interiorly threaded for engagement on the exterior threads 60 on the upper end of the main body of the valve assembly 56 and has a plurality of circumferentially spaced wedge fingers 80 extending downwardly therefrom. The sleeve member 78 has an annuluar shoulder 82 formed on the exterior surface thereof adjacent the upper end of the wedge fingers 80 and the lower end of each wedge finger is provided with an outwardly extending enlarged end 84. Fixedly secured, as by a set screw or the like, to the midportion of the exterior threads 60 of the main body 58 is a stop collar 86.

In mounting the back-pressure valve assembly 56 within the hanger bushing 34 before landing the latter, a service tool, generally indicated at 88, is connected with the back-pressure valve assembly, as shown in FIGURE 2. The service tool '88 comprises a rod or tube 90 having an interiorly threaded sleeve 92 rigidly secured to the lower end thereof and extending below the same for threaded engagement on the upper exteriorly threaded end 60 of the main body of the assembly. A stinger rod 94 extends downwardly from the rod 90 through the sleeve 92 a considerable distance and has its lower end disposed so that when the sleeve 92 is threadedly mounted on the upper end of the main body of the valve assembly, the lower end of the stinger rod 94 will engage the ball valve 74 and maintain the same in spaced relation from the seat 72. The valve assembly is positioned within the hanger bushing with the service tool 88 mounted thereon, as shown in FIGURE 2. The valve assembly is properly positioned within the hanger bushing when the annular shoulder 82 thereof engages the annular shoulder 52 formed within the hanger bushing. It will also be noted that the outwardly extending ends 84 of the wedge fingers will be resiliently urged into the annular groove 54 formed in the hanger bushing.

With the assembly in this position, turning of the service tool will result in a relatively vertical movement between the wedge carrying sleeve 78 and the remaining structure of the valve assembly so that the frusto conical wedge surface 66 will move into engagement with the lower end of the wedge fingers 80, retaining the same firmly within the annular groove 54. A continued turning of the service tool in the same direction utilized to expand the wedge fingers within the annular groove 54 serves to disengage the sleeve 92 from the thread 60 on the upper end of the main body. At the same time, the lower end of the stinger element 94 moves upwardly relative to the seat 72 so that the spring 76 will urge the ball 74 on the seat 72 to close the valve mechanism. With the service tool removed and a suitable pipe or the like (not shown) engaged within the threaded interior of the upper end of the hanger bushing 34, the latter is landed on the hanger seat 42.

In this regard, it will be noted that when the tubing string is landed, an internal pressure of the well will be exerted on the back-pressure valve assembly, tending to blow out the entire tubing string. However, the weight of the tubing string is suflicient to overcome the internal pressure of the well, since there is very little cross-sectional area upon which the internal pressure can act. Moreover, it will be understood that each tubing string is landed while maintaining full control by the use of blowout preventer equipment, such as illustrated in Mueller et a1. patent, No. 2,082,413, issued June 1, 1937, Mueller et al. patent, No. 2,117,444, issued May 17, 1938, Roye patent, No. 2,207,469, issued July 9, 1940, Mueller et al. patent, No. 2,620,880, issued December 20, 1952, and Mtsleller et al. patent, No. 2,624,413, issued January 6, 19 3.

In making up the multiple tubing string well apparatus, each of the tubing strings is landed with a back-pressure valve assembly mounted therein, in the manner indicated above, utilizing such blowout preventing equipment. After all of the tubing strings have been properly landed, the blowout preventing equipment is removed and the flow control equipment of the present invention, which serves to complete the well apparatus, is mounted thereon. The conventional use of such equipment serves to make up what is well known as the Christmas tree of the oil well apparatus.

Referring now to FIGURE 2, a multiple flow con trol head 96 has its lower end suitably formed for connection with the flange 16 of the casing head 10. While any conventional coupling means may be employed to eflfect this connection, there is shown in the drawings an interiorly threaded ring flange 98 threaded on the lower end of the flow head 96 and a sealing ring 100, preferably of the type described in the Watts et al. patents, Nos. 2,766,829, 2,766,998 and 2,766,999, all issued October 16, 1956, is provided between the upper end of the casing head 10 and the lower end of the flow head 96. A series of circumferentially spaced bolts 102 are provided to secure the ring flange 98 to the flange 16 of the casing head so as to effect a proper seal of the sealing ring therebetween. The flow head 96 is provided with circumferentially spaced vertically extending through bores 104, which correspond to the bores 30 formed in the hanger 20. As illustrated, there are three such bores and they are disposed in alignment with the bores 39 within the hanger 20 and, thus, communicate with the respective tubing strings disposed therein. The lower end of each bore 104 is formed with an outwardly and downwardly extending frusto-conical seating surface 106 for engaging the frusto-conical seating surface 46 of the respective hanger bushing 34, with the elements 48 forming a pressure'tight seal therebetween. Extending laterally outwardly from the flow head 96 in circumferentially spaced relation is a series or" lateral branch outlets or nipples 108, each having a passage 111) formed therein which communicates respectively with the associated vertical bore 164. The outer end of each passage 11% is in-teriorly threaded, as at 112, for purposes hereinafter to be more fully described.

The upper end of each here 1114- is interiorly threaded, as at 114, to receive the lower end of a plug, generally indicated at 116. The plug may be of any suitable construction and, as shown, includes a body 118 having its lower end exteriorly threaded for engagement within the associated upper threaded end 114 of the bore 164. A vertical bore 120 is formed in the body 115 and a counterbore 122 extends upwardly from the lower end thereof so as to define an annular valve seat 121. A valve member 126 is disposed within the counterbore 122 in a position to engage the seat 121 and has a valve stem 128 extending from both ends thereof. A coil spring 130 is disposed in surrounding relation to the lower end of the valve stem 128 within the counterbore 1 22 and resiliently urges the valve 126 into seating engagement with the valve seat 121. The spring 135 is retained within the counterbore by means of a centrally apertured ex-teriorly threaded element 152 engaged within the lower end of the counterbore and arranged to loosely receive the lower end of the valve stem 12%. The upper end of the valve stem 128 extends through the bore 120 and terminates within a downwardly extending interiorly threaded countenbore 134 formed in the upper end of the main body. The exterior surface of the upper end of the main body is formed with an angular configuration 136 for engaging a suitable tool arranged to turn the plug so as to insert and remove the same.

The upper end of the multiple flow head 96 is flanged, as at 138, for connection with rotatable cap assembly or cap member 1419 having its lower end correspondingly flanged, as at 142, for connection therewith. Preferably, the flanged ends 1313 and 14 2 of the flow head 96 and cap member 140 are connected together by means of a sealing ring 14-4 and exterior segmental clamping sections or elements 146 and 148 interconnected by bolts 1511. The sealing ring 144 and clamping elements 146 and 14 8 are preferably constructed in accordance with the teachings of any of the above-mentioned Watts et al. patents. More specifically, as shown, the sealing ring 144 is preferably made of metal or the like and includes an external rib portion 144' arranged to seat between the flanges 138 and 142 and integral oppositely disposed flexible lips 144 having exterior frusto-conical surfaces arranged to engage the frusto-conical interior surfaces of the flanges 138 and 142. The clamping sections include opposed interior wedge surfaces 148' arranged to engage the exterior frustoconical surfaces of the flanges 13% and 142 so as to move the same together into engagement with the ring rib por tion 144 therebetween as the bolts 150 are tightened. The connection is such that the bolts 150 may be loosened somewhat so as to render the cap member 140 capable of being rotated about its central vertical axis with re spect to the multiple flow head 96. The cap member 140 is thus mounted in sealing communication with the upper ends of the bores 1M and for rotation about a vertical axis.

The cap member 1411 has a vertical access opening or passage 152 extending therethrough and disposed in a laterally offset position relative to the vertical axis of rotation of the cap 14-6 so that the opening 152 may be aligned with any one of the three bores 104 formed in the flow head 96 and, hence, provide access to the tubing string 32 associated therewith. That is, the axis of the opening 152 is disposed from the vertical axis of the cap a radial or lateral distance equal to the radial distance between the vertical axis of the flow head and hanger 20 and the axis of the bores 104 and 31 formed therein. The

upper end of the cap 140 adjacent the opening 152 is also flanged, as at 154, so as to be connected with a master control valve 156 (partially illustrated in FIGURE 2) having its lower end flanged, as at 158, for connection therewith. Here again, this connection is preferably effected with the use of a sealing ring 1611 and segmental bolted clamping elements 162 and 164 of the type disclosed in the above-mentioned Watts et al. patents. Finally, a flow control valve 166 is suitably mounted on the outer end of each lateral nipple 108 to control flow therefrom in the conventional manner. As before, these connections are preferably accomplished by a sealing ring and segmental bolted clamping elements assembly of the Watts et al. type, such as illustrated in the drawings and indicated at 168.

Operation of FIGURES 1-3 Emb diment As noted above, the tubing strings 32 are landed in the hanger 21) supported in the casing head 10 with the use of conventional blowout preventing equipment secured above the casing head. The landing of each tubing string is accomplished with a back-pressure valve assembly 56 mounted in the associated hanger bushing 34 so that when each hanger bushing is landed within a seat 42 in the hanger 2% the valve assembly will serve to prevent flow through the tubing string 32. After all of the tubing strings have been properly landed in the hanger 20, the blowout preventing equipment is removed and the flow control equipment or the well completion equipment of the present invention is mounted on top of the casing head. It will be noted that the multiple flow head 96 seals with the upper sealing surfaces 46 of the hanger bushings 34 and carries at its upper end the rotatable cap member 1 11 The master control valve 156 is mounted on the upper end of the cap member 140 and flow control valves 166 are mounted on the outer ends of the lateral nipples 103. After the master control valve 156 has been secured in position, the well is made to flow in the following manner. With the use of a stufling box (not shown) on the upper end of the master control valve 156, the service tool 88 is extended through the open master control valve, the access opening 152, and the bore 104 in the flow head aligned with the access opening until the same contacts the back-pressure valve assembly 56. The lower end of the sleeve 92 is then threaded on the upper threaded end 60 of the main body 58 of the valve assembly until the same engages the stop collar 86. During this turning movement of the service tool, the lower end of the stinger rod 54 will move the ball valve 74 off its seat 72, permitting the pressure within the tubing string to pass through the interior of the valve assembly 56 and into the bore 104, passage and bore 152. This pressure is controlled by the valve 166 secured to the associated nipple 1198 and the stufling box (not shown) secured to the master control valve 156. Continued turning of the service tool will move the main body of the back-pressure valve assembly 56 relative to the wedge carrying sleeve 78, thus moving the wedge surface 66 out of contact with the wedge fingers 80. At the end of the turning movement of the service tool, the latter is lifted and will carry with it the entire back-pressure valve assembly 56 so that it can be moved upwardly through the bore 104, access opening 152, and out past the master control valve 156. The latter is then closed and the valve assembly 56 with attached tool 88 removed by removing the stufling box with the master control valve 156 closed.

Next, a suitable service tool (not shown) carrying a plug assembly 116 is mounted on the upper end of the master control valve, as by a stufiing box or the like (not shown), and the master control valve 156 is opened to permit the plug carrying service tool to be moved downwardly through the access opening 152 so that the plug 116 can be engaged within the threaded upper end 114 of the bore 194. When the service tool is removed from the plug assembly 1 16, the valve 126 thereof is biased to close so that the 7 pressure within the associated tubing string is retaining now under the control of the valve 166 connected with the associated nipple 108. At this stage, the flow control valve 166 may be opened to permit flow through the associated tubing string 32.

Next, the bolts connected with the clamping elements 146 and 148 are loosened somewhat so as to permit the cap member 140 to be rotated so that the access opening 152 will become aligned with another of the bores 104. After the rotation of the cap member has been accomplished, the bolts 1519 are then secured and the backpressure valve assembly 56 is removed from the hanger bushing 34 disposed within the associated bore 104 in the manner previously indicated. Finally, the plug 116 is inserted in the upper threaded end 114 of the associated bore 16-4, in the manner previously indicated, so that fiow through the associated nipple passage 11% can be controlled by the valve 166 connected therewith. The above procedure is also repeated to flowingly connect the third tubing string to its associated nipple passage and control valve 166.

It will be understood that if for any reason it is desired to gain access to any one of the tubing string 32, as for example, where repairs or other procedures are to be accomplished, the rotatable cap assembly 14-0 will permit such access. That is, it is necessary merely to align the access opening 152 of the cap member with the bore 104 to which access is desired and to remove the plug 116 associated with the tubing string in the manner indicated above and, subsequently, to perform the necessary operations, while at all times controlling the pressure within the associated tubing string 32 by the single master control valve 156 disposed above the cap member. It will be understood that other types of control equipment can be placed above the master control valve 156, if desired. For example, blowout preventing equipment (not shown) can be placed above to insure safe operation of any equipment that is utilized after gaining access to the tubing string. After the access operations have been completed, the plug '116 is simply replaced in the threaded upper end 114 of the associated bore 164 and controlled flow can be continued by the operation of the valve 166 connected with the associated nipple 108. Of primary significance is the fact that access to any one string can be had while the other two are in controlled flow condition.

Another possibility with the present arrangement is that a back-pressure valve assembly 56 may be reinstalled within any one hanger bushing 34 during access, which permits the control valve 166 connected with the associated nipple 108 to be removed for replacement or repair. While this arrangement is possible, it is contemplated that repair or removal of the control valves 166 connected with the nipple 198 can be accomplished by an arrangement such as disclosed in Yancey patent, No. 2,250,244, issued July 22, 1941. That is, the control valves 166 connected with the nipples may be provided with a plug inserting and removing apparatus (not shown) arranged to insert an ex teriorly threaded plug (not shown) within the interiorly threaded end 112 of the associated pasasge 110.

It can be seen that the well completion equipment described above and shown in FIGURES 1-3 thus enables the operator to gain access to any one of a plurality of tubing strings, while the others are in a controlled flow condition, by the use of a single master control valve mounted so that service tools and control equipment may be conveniently used therewith.

Referring now more particularly to FIGURES 4-6, there is shown another form of well completion equipment embodying the principles of the present invention. As shown, the well apparatus includes a casing or tubing head 16 having a multiple hanger 20 landed therein and a plurality of tubing strings landed in the multiple hanger. The tubing strings are made up and landed in the same manner as that indicated in the embodiment of FIGURES 1-3. The completion equipment includes a flow head 96 of substantially identical construction to the flow head 96 previously described. However, a modified rotatable cap assembly is provided on the upper end of the flow head 96, which cap assembly embodies means for removing and inserting the plug in the upper threaded end 114 of the vertical bores 104 in the flow head 96. As best shown in FIGURES 4 and 5, the cap assembly 170 comprises a sleeve-like outer member 172 having a flange 173 formed on its lower end for connection with the flange 138 of the flow head by a sealing ring 144 and segmental clamping elements 146 and 148 secured together by bolts 156 shown as being of the Watts et al type.

Formed on the interior of the outer sleeve element 172 is an inwardly extending annular shoulder 174 defining a cylindrical opening 176 arranged to rotatably receive the lower cylindrical end .178 of an inner rotary cap member The shoulder 174 has an annular groove 182 formed in the center portion thereof for receiving an annular sealing element 184, which preferably is of the type illustrated in Lemley et al. patent, No. 2,485,497, issued October 18, 1949. To this end, the outer sleeve member 172 is formed with passages 186 which communicate with the annular groove 182 at their inner ends and have their outer ends interiorly threaded to receive exteriorly threaded ends of a pair of bolts 188. The interior of the outer sleeve member 172 adjacent the upper end of the shoulder 174 extends upwardly and outwardly and an annular thrust bearing 19d is disposed adjacent the upper end of the shoulder for engaging the lower end of an outwardly extending annular flange 192 formed on the center portion of the inner rotary cap member 180. Mounted within the outer sleeve member 172 in a position above the annular flange 192 and in surrounding rela tion with the rotary member 186 is a roller bearing assembly 194, which may be of any suitable construction. The upper end of the outer sleeve member is interiorly threaded to receive an exteriorly threaded bearing retaining ring 196 arranged to engage the upper end of the roller bearing assembly. It can thus be seen that the inner cap member 130 is rotatably mounted within the outer member and etfectively sealed against excessive pressure conditions by the annular sealing element 184. It has been found that the sealing arrangement provided is effective and also enables the inner member to be readily rotated under such conditions.

The inner cap member 181 is formed with a vertical access opening 193, which has its axis offset from the axis of rotation thereof. More specifically, the axis of the opening 198 is offset from the axis of rotation a radial distance equal to the radial distance between the axis of the flow head 96 and multiple hanger 20 and the axis of the bores 104 and 36 respectively therein. Thus, the access opening 198 can be brought into alignment selectively with any of the three bores 164 provided in the flow head 96 and, correspondingly, with any of the tubing strings 32 carried by the multiple hanger 2t Preferably, the inner cap member includes an upper nipple extension 200 through which the opening 198 extends and the upper end thereof (not shown) is suitably flanged or otherwise provided with suitable means for connecting the same to the lower end of a master control valve (not shown), such as the master control valve 156 illustrated in FIGURE 2.

The primary advantage of the arrangement illustrated in FIGURES 4-6 is that the inner rotary cap member 180 of the cap assembly has embodied therein means for removing and inserting the plugs arranged to be mounted in the upper threaded ends 114 of the bores 104-. As best shown in FIGURES 4 and 5, the inner rotary cap member includes a relatively small through bore 292 which, as shown, has its axis disposed from the axis of rotation a radial distance equal to the radial distance between the axis of rotation and the axis of the opening 198. As shown, the bore 202 is disposed in diametrically opposed relation to the opening 198, however, it will be understood that this position of the bore is not essential and that it may be angularly disposed with respect thereto. An annular groove 204- is formed in the inner rotary cap member 180 in communication with the bore 202 for receiving an annular sealing element 2% arranged to contact the exterior surface or" a rod or stem 203. The annular sealing element 2% preferably is of the same type as that illustrated at 134 and has passages 21d communicating therewith and with the exterior of the rotary member. The outer end of these passages are suitably threaded to receive plugs 212 or the like.

The upper end of the bore 202 is formed with a counterbore 214 having a lower end arranged to rotatably receive the flanged lower end of nut member 216. The upper end of the nut member 216 is interiorly threaded for engagement with an exteriorly threaded upper end 218 of the stem 2%. The upper extremity of the stem 208 is preferably formed so as to have an angular cross-section, as indicated at 224), so as to receive a suitable turning tool (not shown). In order to retain the nut member 216 within the counterbore 214, the upper end of the latter is interiorly threaded to receive an exteriorly threaded retaining ring 222 arranged to engage the upper surface of the lowered flanged end of the nut member 216.

Because the stem 2% is positively retained in position by the inner rotary cap members 180 of the cap assembly, it is not necessary to utilize valve containing plugs, such as the plugs 116 previously described, in the upper threaded ends of the bores 16 5. As best shown in FEGURES r and 5, a solid plug 224 is utilized and the tendency of the same to blow out when disengaged from its threaded connection within the bore or engaged therein, as a result of the pressure in the associated tubing string 32, is sufficiently resisted and controlled by the rigid securement afforded by the stem 2%. Each plug 224 may be of any suitable construction and, as shown, includes an upper frusto-conical seat having sealing elements 225 mounted therein for engaging a corresponding seat formed in the upper end 114 of each bore 104. In order to engage and disengage the stem 208 with the plugs 224, each of the plugs is provided with a socket 226 in its upper end, which socket is of angular cross-sectional configuration, the hexagonal configuration shown being preferred. The lower end of the stem 208 is provided with a correspondingly formed cross-sectional configuration, as indicated at 228, so that the same may seat into the socket 226. Preferably, spring-pressed balls 230 or the like are provided in the end 228 to frictionally retain the plug in engagement with the end 228, as shown in FIGURE 4.

Operation of FIGURES 4-6 Embodiment As briefly noted above, the multiple tubing strings 32 are landed on the multiple hanger 20 and the well apparatus is made up in the same manner previously indicated with respect to the embodiment illustrated in FIGURES 1-3. The flow head 96 and the cap assembly 170 are suitably mounted on the tubing head in the same manner as previously indicated with the hanger bushings 34, each having aback-pressure valve assembly 56 mounted therein to prevent flow through the associated tubing string 32. The flow head 96 is mounted on the tubing head it), with each bore 104 thereof provided with a plug 224 in its upper threaded end 114. After the cap assembly 179 has been secured to the upper end of the flow head and a master control valve 156 has been secured to the upper end of the nipple extension 2% of the cap assembly, the inner rotary cap member 180 is rotated until the stem 2% is aligned with one of the plugs 224. Of course, the master control valve will be closed preparatory to the removal of the plug.

In the operation of the plug removing and inserting stem 2%, it will be noted that the upper end 220 thereof may be fitted with a suitable rotating tool to turn the stem initially into substantial engagement with the upper end of the plug 224 while the nut member 2 16 is held against rotation. Next, the nut member 216 is turned and the stem 2% is held against rotation, which effects a translationally downward movement of the stem so that the lower end 228 thereof will engage within the socket 226 of the plug 224:, as shown in FIGURE 5. Next, the stem is rotated by end 220 in a direction suitable to remove the plug 224 from the upper threaded end 114 of the bore 104 while the nut member 216 is held against rotation. After the plug has been removed, the inner cap member is rotated 180 into the position illustrated in FIGURE 4, so that the access opening 198 will be aligned with the bore 104 from which the plug has been removed.

With the cap assembly in the position shown in FIG- URE 4, a service tool, such as the tool 88, can be secured, as by stuffing box or the like, to the upper end of the master control valve and lowered through the access opening 1% in the cap assembly 170, the bore 104 in the flow head 96 and, finally, into the interior of the associated hanger bushing 34. The service tool 88 may be operated to remove the back-pressure valve assembly 56 mounted in the associated hanger bushing 34 in the manner previously indicated. After removal has been effected and the master control valve closed, the inner cap member 1230 is again rotated 180 and the plug 224 is engaged within the upper threaded end of the bore 104 by reversing the stem operating procedure described above. With the plug 224 in place and the back-pressure valve assembly 56 removed, flow through the associated tubing string 32 may be commenced by opening the control valve on the outer end of the associated nipple 108. In a like manner, the back-pressure valve assembly 56 in the remaining tubing strings 32 are removed so that flow may be commenced therein in the same manner.

It is significant to note that in the embodiment dis closed in FIGURES 4-6, access to any one of the tubing strings can readily be accomplished by removing the associated upper plug 224 through the operation of the stem 2%. Such removal can be effected without the need of manipulating the master control valve mounted above the cap assembly 170. That is, the latter remains closed during the removal of the plug and control is maintained at all times. The arrangement shown in FIG- URES 46, of course, permits access to the tubing strings for any of the purposes previously mentioned and, as before, access to any one tubing string does not necessitate interruption of the flow condition of the remainder.

it thus will be seen that the objects of this invention have been fully and eifectively accomplished. It will be realized, however, that the foregoing specific embodiment has been shown and described only for the purpose of illustrating the principles of this invention and is subject to extensive change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.

We claim:

1. Well head completion equipment for gaining access through a flow head having a plurality of circumferential-ly spaced vertical bores therein and flow passages extending laterally from said bores to a plurality of circumferentially spaced tubing strings carried by a casing head in communication with the vertical bores of the flow head comprising cap means for securement to said flow head in communication with the upper ends of the vertical bores, said cap means including a member having a vertical access opening extending therethrough, and means connected with said member mounting the same in sealing communication with said flow head bores for rotation about a vertical axis spaced laterally from the axis of said access opening, said member being rotatable to selectively align said access opening with any one of the vertical flow head bores in communication with said cap means, said member also having a vertical bore therein, said bore having its axis spaced from said axis of rotation 1 1 a distance equal to the spacing of the axis of said opening therefrom, and a plug removing and inserting tool mounted within said cap means bore for rotational and longitudinal movement.

2. Well head completion equipment for use with a casing head having a plurality of circumferentially spaced tubing strings supported therein comprising a multiple flow head having means defining a plurality of circumferentially spaced vertical bores extending therethrough, said flow head being mountable above and upon the casing head with said bores aligned and communicating respectively with the tubing strings in the casing head, each of said vertical bores having a lateral passage communicating therewith, a cap member having a vertical access opening extending therethrough, means mounting said cap member on the upper end of said multiple flow head in sealing engagement therewith and for rotation about a vertical axis spaced laterally from the axis of said access opening so that the latter may be selectively aligned with any one of the vertical bores within said flow head, and closure means associated with said vertical bores operable to provide selective access thereto via said cap member access opening.

3. Well head completion equipment as defined in claim 2 wherein the upper end of said flow head and the lower end of said cap member are provided with annular flanges and wherein said mounting means comprises a sealing ring of hard metal or the like having a centrally disposed external rib portion extending between said annular flanges and oppositely disposed flexible ribs sealingly engaging the interior of said flanges and exterior clamping sections engaging the exterior of said flanges and biasing the same together.

4. Well head completion equipment as defined in claim 2 wherein said mounting means comprises an outer sleeve-like member rigidly secured in sealing engagement to the upper end of said multiple flow head and rotatably receiving said cap member.

5. Well head completion equipment as defined in claim 4 wherein said sleeve-like member has an annular shoulder formed on the interior thereof defining a cylindrical surface and wherein the lower end of said cap member is formed with a corresponding cylindrical surface engaged within said first-mentioned cylindrical surface, and sealing ring means mounted between said cylindrical surfaces.

6. Well head completion equipment as defined in claim 5 wherein said cap member includes an outwardly extending annular flange disposed above the lower end thereof and seating on the annular shoulder formed on the interior of said outer member, a bearing race mounted on the upper surface of said annular flange and a retaining ring mounted within the upper end of said outer member in engagement with said bearing race.

7. Well head completion equipment for use with a casing head having a plurality of circumferentially spaced tubing strings supported therein comprising a multiple flow head having means defining a plurality of circumferentially spaced vertical bores extending therethrough, said flow head being mountable above and upon the easing head with said bores aligned and communicating respectively with the tubing strings in the casing head, each of said bores having a lateral flow passage communicating therewith, rotatable cap means supported by said flow head in a position thereabove for rotation about a vertical axis and having a vertical access opening therein laterally offset from the axis of rotation for selective alignment with said vertical bores in response to rotation of said cap means, and closure means for closing each of said vertical bores above said lateral passages and for permitting the selected bore aligned with said access opening to be opened While the remainder of said bores are closed so that access to the associated tubing string can be obtained.

8. Well head completion equipment for use with a casing head having a plurality of circumferentially spaced tubing strings supported therein comprising a multiple flow head having means defining a plurality of circumferentially spaced vertical bores extending therethrough and being arranged to be mounted above and upon the casing head with said bores aligned and communicating respectively with the tubing strings of the casing head, each of said vertical bores having a lateral flow passage communicating therewith, cap means disposed above said multiple flow head, means mounting said cap means on said multiple flow head in sealing engagement therewith and for rotation about a vertical axis, said cap means having a vertical access opening therein laterally offset from the axis of rotation for selective alignment with said ver tical bores in response to rotation of said cap means, and aplug removably mounted in the upper end of each of said vertical bores so that any one of said plugs can be removed from its associated vertical bore and the access opening of said cap means aligned with said bore to obtain access to the associated tubing string.

9. Well head completion equipment as defined in claim 8 wherein said cap means includes plug removing and inserting means mounted therein for longitudinal movement along and rotary movement about a vertical axis disposed laterally from the axis of rotation thereof a distance substantially equal to the lateral distance between the axis of said access opening and said axis of rotation.

10. Well head completion equipment as defined in claim 9 wherein said plug removing and inserting means comprises a stem mounted for rotational and longitudinal movement within a vertical bore formed in said cap means, and means on the lower end of said stem for removably fixedly engaging said plugs.

11. Well head completion equipment as defined in claim 10 wherein said plug removing and inserting means fuither includes means between said cap means and the upper end of said stem for imparting either a rotary longitudinal movement or a translational longitudinal movement to said stem.

12. Well head completion equipment as defined in claim 11 wherein said last-mentioned means comprises a nut member threadedly engaged on the upper end of said stem and means mounting said nut in said cap means for rotational movement about the axis of said stem and for preventing longitudinal movement thereof relative to said cap means.

13. In an apparatus of the type described, the combination comprising: a casing head having means therein for receiving and supporting a plurality of circumferentially spaced tubing strings, a flow head supported by said casing head in a position thereabo-ve and having means defining a plurality of circumferentially spaced vertical bores extending therethrough in a position axially aligned with said tubing string supporting means for communication respectively with the tubing strings supported thereby, each of said vertical bores having a lateral flow passage extending therefrom, means supported by said flow head in a position thereabove for rotary movement about a vertical axis equidistant from each of the axes of said Vertical bores, said means having a vertical access opening therein with its axis spaced from said axis of rotation a distance substantially equal to the distance of each of the axes of said vertical bores to said axis of rotation so that said access opening will be selectively aligned with said bores during rotation of said means, and closure means for closing each of said bores above the lateral passages therein, said closure means being operable to permit opening of the selected bore aligned with said access opening with the remainder closed so that access to the associated tubing string will be obtained.

14. In an apparatus of the type described, the combination comprising: a casing head having a frusto-conical seat formed therein, a multiple tubing string hanger engaged on said seat and having a plurality of circumferl3 entially spaced bores extending therethrough, each of said bores having a frusto-conical upper end providing a seating surface, a plurality of tubing hangers having tubing strings secured thereto, each of said tubing hangers having a lower frusto-conical seating surface engaging a seating surface of said multiple tubing string hanger and an upper frusto-conical seating surface, a flow head secured to said casing head and having a plurality of circumferentially spaced vertical bores extending therethrough in axial alignment with the bores of said multiple tubing string hanger, the lower ends of said flow head bores being formed with frusto-conical seating surfaces engaging the upper seating surfaces of said tubing string hangers to provide a seal therewith, each of said flow head bores having a lateral flow passage communicating therewith, control valves connected with said flow head for separately controlling the flow through said lateral flow passages, the upper end of each of said flow head bores having a plug removably mounted therein, rotatable cap means mounted on the flow head for rotation about a vertical axis, said rotatable cap means having a vertical access opening formed therein in a position laterally offset from the axis of rotation for selective alignment with the flow head bores in response to rotation with said rotatable cap means so that by selectively removing the plug associated with the bore aligned with said opening access to the associated tubing string will be obtained and a master control valve mounted above said flow head for controlling said access opening.

15. The combination as defined in claim 14 wherein Said cap means includes plug removing and inserting means mounted therein.

References Cited in the file of this patent UNITED STATES PATENTS 2,335,355 Penick et al Nov. 30, 1943 2,522,444 Grable Sept. 12, 1950 2,708,975 Schaefer May 24, 1955 2,713,909 Baker July 26, 1955 2,766,829 Watts et al Oct. 16, 1956 2,794,505 Allen June 4, 1957 2,885,005 Rhodes May 5, 1959 2,889,886 Gould June 9, 1959 FOREIGN PATENTS 1,054,938 Germany Apr. 16, 1959 

